Can a WorkerThread do a SendMessage to a CDialog

[ForNow]

Hi, I have a Worker thread started in my main thread CWinAPP and I am trying to do a SendMessage to a CDIalog seems I can only do a Send/PostMessage to the CMainFrame Main Window can someone corrabrate or dispute this and if so is there a way to get a Message to the CDialog thanks

[Sivaraman Dhamodharan]

What kind of communication you want to make with the dialog? Is that dialog is alive when you send the message? Note that the Post message will not block your thread, and sendmessage will.

Programming Article

[CPallini]

Before trying to use threads to communicate with the GUI I strongly suggest you reading some Newcomer's articles about. You may start, for instance with "Using Worker Threads"[^].

Veni, vidi, vici.

[ForNow]

The Thread is Created in the CWinApp::Initinstance seems like either Send/PostMessage always references the MainWinow CMainFrame I keep on getting CInvalidArg exception because my WIndow Handle is the CDialog

[Eugen Podsypalnikov]

Please answer :) : - Whereby does the secondory thread know the dialog ? - When will the first message be sent ?

They sought it with thimbles, they sought it with care; They pursued it with forks and hope; They threatened its life with a railway-share; They charmed it with smiles and soap. :)

[ForNow]

I save a CWnd * or Cialog * pointer in a global object on the heap The thread retervies that pointer However it seems that the Send/PostMessage can only send messages to the CMainFrame

[Eugen Podsypalnikov]

Do you have such an "if" statement ? :) :

{
//..

HWND hDlg = g_pcDialog->GetSafeHwnd();
if (hDlg) {
::SendMessage(hDlg, WM_COMMAND, IDOK, 0);
}

//..
}

They sought it with thimbles, they sought it with care; They pursued it with forks and hope; They threatened its life with a railway-share; They charmed it with smiles and soap. :)

[Albert Holguin]

ForNow wrote:

However it seems that the Send/PostMessage can only send messages to the CMainFrame

That's not true... you can post messages to any HWND[^] (which is the appropriate method versus saving a CWnd or CDialog). In another words, you can send messages to anything that has a window associated with it (not the only way, but it's a good generic statement), which sort of leads to a common way of messaging to classes that don't have other framework characteristics, make an invisible window for them that others can use as messaging targets.

[Chuck OToole]

Note that SendMessage() cannot be used to send messages to controls that were *not* created by the thread sending the message. See my answer to This Question[^]